The present invention relates generally to an electronic sequence type controller and, more particularly, to a sequence type controller suitable for operating various types of sequentially operated apparatus, including household appliances such as clothes washing machines or the like, and which has substantial programming flexibility.
In recent years, a number of electronic control circuits for appliances, particularly dishwashers and clothes washing machines, have been proposed. Such controllers are intended to replace the electromechanical timer/sequencers which heretofore have been employed in this class of household appliances.
Such electronic controllers typically include a sequencer element in the form of a digital counter, with each counter state representing a program step. In order to advance the sequencer counter through its respective counting states, periodic clock pulses are applied to the counter. For driving various external load devices in the appliance, for example water valve solenoids, digital decoding logic is typically connected to the sequencer counter to sense the particular state thereof and to operate the external load devices when appropriate. Additionally, since different time durations are generally desired for different steps in operation cycle, a number of prior art controllers have included various means for altering the time durations of particular steps. Lastly, various controllers have included means for altering the sequence of program steps depending on external inputs.